A problem associated with such shoe is that after wearing the shoe for some time the tongue slips, regularly towards the outer side of the foot. In particular, with shoes for sportive leisure time activities such as hiking boots, mountaineering boots or sports shoes, during which the foot is frequently moved to a large degree, a correspondingly large degree of friction against the shoe is generated, thus causing painful pressure sores or abrasions, when the tongue is not in its correct position relative to the foot. One reason for the slipping effect is that the tongues are usually preformed. In the process of performing they are precurved along the foot contour and, if necessary, along the contour of the lower leg. Depending on the material and the design of the tongue the preform can be attained in many different ways. Multi-layered tongues made of textile or/and leather materials, for instance, can obtain their preform by superimposing individual, non-preformed material layers of the tongue in the desired shape. By suitable stitching or glueing of the material layers a permanent preform can be attained. If plastics parts made of flexible plastics material are used for the tongue, the plastics parts can be manufactured in the desired form, e.g. by injection moulding. It is also conceivable to press the tongue into its desired shape. If, during walking, the forefoot or metatarsus is now bent towards the tibia (shin), the tongue is correspondingly bent in the ankle flexure portion. In order to retain its preformed shape the tongue thus slips away from the lower leg pressing towards the front. The consequence is that it slips to the side. The reason why in most cases it slips to the outer side of the foot can be found in the anatomical differences between the foot-outside and the foot-inside. Usually these anatomical differences are not taken into account in performing the tongue; a symmetrical shape is much rather given to the tongue with respect to a cross-section taken transverse across the instep.
The slipping of the tongue can be particularly painful in shoes or boots with ankle height or shin height with tongues that extend over the ankle flexure portion of the shoe, since in such cases the tongue can easily slip over the ankle, in particular over the lateral malleolus, where abrasions or pressure sores are particularly painful and considerably impair the wearing comfort.